1. Field of the Invention
The present invention relates to a noncontact transmitting apparatus for making noncontact connections between a main device and an attachment device like a camera, which main device includes a mobile information terminal like a cellular phone or mobile personal computer, a game machine, an AV (audio-visual) machine, a medical device, an industrial machine and an environmental monitoring device.
2. Description of Related Art
Conventionally, although a cellular phone with an integrated a camera is known, there have been few cellular phones with an attachable/detachable camera.
As for a mobile personal computer, Japanese patent application laid-open No. Hei. 9-26834 discloses a technique that transfers power and data using electromagnetic induction. The mobile personal computer has two sets of a magnetic core and coil, each attached to the backs of its body and display about its hinge to transfer power and data from the body to the display by electromagnetic induction, thereby reducing disconnections that can happen due to stress imposed by the hinge.
With the foregoing arrangements, the conventional mobile information terminals have the following problems. First, as for the cellular phone, since the camera is embedded therein, it cannot be attached to the cellular phone only when needed, and hence cannot be detached to utilize it for other purposes.
As for the conventional technique disclosed in Japanese patent application laid-open No. Hei. 9-26834, although it can transfer power and data from the body to the display of the mobile personal computer, it is not designed for carrying out noncontact transfer of power and data from the main body of the cellular phone to the camera. Thus, it is not applicable to the technique for enabling the camera to be attached to and detached from the cellular phone.
The present invention is implemented to solve the foregoing problem. It is therefore an object of the present invention to provide a noncontact transmitting apparatus transferring signals and power between a mobile device and its attachable/detachable camera with a simple configuration and high reliability, when the camera is mounted on the mobile device.
According to a first object of the present invention, there is provide a noncontact transmitting apparatus comprising: a first noncontact transmitting unit mounted on a main device; a second noncontact transmitting unit mounted on an attachment device, the second noncontact transmitting unit being removably attachable to the first noncontact transmitting unit, for enabling noncontact signal transfer between the main device and the attachment device, wherein each of the noncontact transmitting units comprises: a power coil wound on a first core to supply power from the main device to the attachment device by means of electromagnetic induction effect, wherein the first core of the first noncontact transmitting unit and the first core of the second noncontact transmitting unit face each other at a first opposite position when the attachment device is loaded on the main device; and at least one signal coil wound on at least one second core to carry out signal transfer between the main device and the attachment device by means of electromagnetic induction effect, wherein the second core of the first noncontact transmitting unit and the second core of the second noncontact transmitting unit face each other at a second opposite position when the attachment device is loaded on the main device.
Here, the second noncontact transmitting unit may be rotatably attached to the first noncontact transmitting unit about the first core, and when it is rotated about the first core by a specified angle, the signal coil of the second noncontact transmitting unit may be shifted from the second opposite position.
Each of the noncontact transmitting units may further comprise means for fixing and integrating the power coil and the signal coil at their specified positions.
The power coil may disposed close to a facing surface of the first core, and the signal coil may be disposed close to a facing surface of the second core.
The main device may further comprise an antenna for transmitting and receiving a signal.
Each of the noncontact transmitting units may further comprise: a circuit board that includes, in addition to the power coil and the signal coil, conductor patterns to the power coil and signal coil, and ground through holes; a flexible printed circuit for transmitting signals to the conductor patterns; and chip capacitors for feeding an antenna signal passing through the flexible printed circuit back to ground through the ground through holes.
Each of the noncontact transmitting units may further comprise: means for fixing and integrating the power coil, the signal coil, the conductor patterns and the chip capacitors at their specified positions; and a metallic thin-film shield for covering the noncontact transmitting unit, which is integrated by the means, to prevent the antenna signal from penetrating the noncontact transmitting unit.
The circuit board may consist of a double-layer circuit board, and the conductor patterns may be formed on an internal layer of the double-layer circuit board.
Each of the noncontact transmitting units may further comprise means for fixing and integrating the power coil and the signal coil at their specified positions.
Each of the noncontact transmitting units may comprise a metallic thin-film shield for covering said noncontact transmitting unit to prevent the antenna signal from penetrating said noncontact transmitting unit.
The metallic thin-film shield may comprises hole on its facing surface.
The metallic thin-film shield may comprise lattice-like patterns on its facing surface.
The metallic thin-film shield may be covered with an insulating coating.
The first noncontact transmitting unit may further comprise a magnetic shield for preventing leakage flux from the first noncontact transmitting unit from affecting a radio frequency circuit in the main device.
The main device may consist of a cellular phone and the attachment device may comprise a camera.
According to a second aspect of the present invention, there is provide an information system comprising: a main device; an attachment device; a first noncontact transmitting unit mounted on the main device; a second noncontact transmitting unit mounted on the attachment device, the second noncontact transmitting unit being removably attachable to the first noncontact transmitting unit, for enabling noncontact signal transfer between the main device and the attachment device, wherein each of the noncontact transmitting units comprises: a power coil wound on a first core to supply power from the main device to the attachment device by means of electromagnetic induction effect, wherein the first core of the first noncontact transmitting unit and the first core of the second noncontact transmitting unit face each other at a first opposite position when the attachment device is loaded on the main device; and at least one signal coil wound on at least one second core to carry out signal transfer between the main device and the attachment device by means of electromagnetic induction effect, wherein the second core of the first noncontact transmitting unit and the second core of the second noncontact transmitting unit face each other at a second opposite position when the attachment device is loaded on the main device.